With development of intelligent terminals and mobile Internet, higher requirements on capacities of wireless networks are proposed. A data service characteristic of mobile broadband is asymmetrical uplink and downlink data traffic, and downlink data traffic is far greater than uplink data traffic. In this case, in a system with symmetric broadband, downlink load is far greater than uplink load. Therefore, requirements of the mobile broadband development on the capacities are mainly requirements on downlink capacities.
A traditional capacity expansion solution includes adding a system carrier and adding a site. However, an operator has to face limited wireless spectrum resource, a difficulty in site acquisition, and high costs of establishing a new site. A sector splitting (cell splitting) technology splits an original sector having a relatively high capacity requirement into multiple sectors, which provides a low-cost capacity expansion solution without adding a site or adding a system carrier.
Traditional cell splitting uses a manner in which uplink splitting and downlink splitting are performed simultaneously; consequently, there may be a problem that a difference between uplink coverage and downlink coverage increases.